Despite the widespread concern about drug use and abuse by young Americans, alcohol remains teen-agers' most widely used mind-altering substance and the one that is most likely to get them into trouble. In one national survey, nearly a third of high school students who drank at all were ''alcohol misusers'' or ''problem drinkers'' -- that is, they had been drunk at least six times in the previous year or had had serious difficulties two or more times that year as a result of drinking.

In addition to causing school problems, destructive and delinquent behavior and violence, alcohol is the leading factor in fatal and non-fatal traffic accidents involving teen-age drivers. Although teen-agers represent only 10 percent of licensed drivers, they account for 20 percent of highway fatalities, and the vast majority of youthful accidents involve alcohol.

Furthermore, because of inexperience in driving and in handling alcohol, teen-age drinking-related accidents tend to occur at much lower blood alcohol levels than do adult accidents. Each year 5,000 young lives are lost in such accidents.

According to a report last month in the Journal of the American Medical Association, alcohol abuse in early adolescence is a strong predictor of later alcohol abuse and other drug problems. But those who neither smoke nor drink as teen-agers are virtually immune to later drug abuse.

Thus, it is the misguided parent who is relieved to discover that his or her teen-ager drinks alcohol but steers clear of other drugs.

Directly or indirectly, parents play the major role in determining their children's alcohol use patterns. By learning more about these patterns and the factors that influence them, parents can do more than any educational program or legal restriction to reduce the likelihood that their children will abuse alcohol or suffer an alcohol-related injury inside or outside the home.

This should not be taken to mean that schools should ignore educational efforts or that states should lower the minimum drinking age or ease off on penalties for teen-agers who drive when drunk. (In several states, raising the minimum drinking age to 21 reduced teen-caused traffic fatalities by about 20 percent.) But it does suggest that it is time for parents to stop pointing the finger of responsibility at peer-group and advertising pressures and social glamorization of alcohol as the primary causes of alcohol abuse by youngsters. Although peer-group influences may predominate during the mid-teen years, parental influences dominate earlier and reassert themselves as children get older. They also tend to be long lasting.

According to a new survey of 44,326 youngsters released last month by the National Parents' Resource Institute for Drug Education, children today start drinking alcohol at an earlier age and drink more frequently than in the past. The survey revealed that 33.4 percent of current sixth-graders had tried beer or wine and 9.5 percent had tried hard liquor.

By contrast, among the 12th-graders interviewed, only 14.5 percent had tried beer or wine and 6.8 percent had tried hard liquor by the time they were in the sixth grade. According to the survey, alcohol use at least once a week by sixth-graders more than doubled from 1983 to 1984. The percentage of high school seniors who drank beer or wine at least three times a week nearly doubled.

At least one recent study of college students who vacation in Fort Lauderdale suggests that since 1981 alcohol consumption has fallen 13 percent among college men and 25 percent among college women.

The difference in the proportions of college freshmen and seniors who drink has been shrinking, suggesting that more children today start drinking either before they leave high school or immediately after entering college. And there has been an increase in drinking and in excessive drinking by girls both in high school and college, reflecting the growing social equality of boys and girls.

There are clear social-class and racial differences in teen-age alcohol use and abuse. Overall, drinking and heavy drinking by young people are more common among lower socioeconomic groups. Among young people still in school, fewer black students than white students are drinking heavily or at all.

Studies have shown that many factors influence teen-age drinking habits, but that parental attitudes and actions can influence them all.

For some teen-agers, alcohol is a means of coping with or blotting out some terrible aspect of their lives -- parental divorce, destitute living conditions, physical or sexual abuse and the like. For others, heavy drinking represents an attempted escape from serious emotional or personality problems, such as poor self-image, feelings of parental hostility and lack of love, immaturity and impulsiveness, and rebellion against excessive parental controls.